Ionic Bonds and Compounds Ionic Bonds and Compounds

Ionic Bonds and Compounds

Ionic Bonds and Compounds (in a future unit we'll learn about covalent or molecular bonds and compounds)

Ionic Bonds and Compounds Dogs can teach chemistry!

Ionic Bonds and Compounds So can stick figures. . .

Except for the noble gasses, atoms of all elements are unstable! All chemical reactions occur so atoms can achieve stability. Atoms achieve stability when they have full electron energy levels. That is, when they have a "noble gas configuration" of electrons.

Metals, having 1, 2, or 3 valence electrons, can become stable (full energy levels) by losing electrons. When metals lose electrons, they become positive ions, known as cations.

Non-Metals Non-metals, having 5, 6, or 7 valence electrons, can become stable (full energy levels) by gaining electrons. When non-metals gain electrons, they become negative ions, known as anions.

So. . . metals form positive ions non-metals form negative ions

So. . . metals form positive ions non-metals form negative ions

Mini-Quiz #1 What charge do the following atoms have when they lose or gain electrons to become ions? Li Cl Mg Na O Al S N Se P F Ca Br K Be Al Ba Fr

BUT. . . atoms can't just gain or lose electrons in isolation. They must have another atom to give to or take electrons from. Metals (that want to lose electrons), transfer electrons to nonmetals (that want to gain electrons). The metal atoms become positive ions, and the nonmetal atoms become negative ions. These oppositely charged ions attract each other forming IONIC BONDS.

Using Lewis Dot structure to understand Ionic Compound formation (remember: Lewis Dot structures consist of an atom's symbol surrounded by dots representing valence electrons) Na + Cl Mg + O

Mg + Cl Na + O Al + Cl Al + O

Ions always combine in ratios that neutralize the charges. So the ionic compound has an overall zero charge. Ionic compound formulas are always written with the positive ion first!

2+2 4 landscape

Mini Quiz #2 Balance the following formulas A Ca Cl Ca O Na N K Cl KO Ba N B Na F Na S Na O Mg N Ba O Na Br

Polyatomic Ions As the name implies, polyatomic ions are made of several atoms. These atoms are joined by strong covalent bonds (which we'll study in another unit). For now, just think of them as a group of atoms glued together that, as a group, have a charge.

Polyatomic Ions Polyatomic ions are everywhere and are important. The sooner you learn to recognize them, the easier your understanding of chemistry will be. You will need to memorize 10 of the most common (there are MANY more).

The ten you need to know are: Ammonium NH 4 Sulfate +1 SO 4 Carbonate Nitrate NO 3 -1 Cl. O 3 Chlorate -1 Permanganate -1 Acetate -1 Hydroxide Mn. O 4 OH -1 -2 Chromate Cr. O 4 -2 Phosphate C 2 H 3 O 2 -2 CO 3 PO 4 -3

C 2 H 3 O 2 NH 4 Acetate -1 Ammonium +1 CO 3 Carbonate -2 Cl. O 3 Chlorate -1 Cr. O 4 Chromate -2 OH Hydroxide -1 NO 3 Nitrate -1 Mn. O 4 Permanganate Phosphate -3 SO 4 Sulfate -2 -1

Acetate C 2 H 3 O 2 -1 Ammonium NH 4 +1 Carbonate CO 3 -2 Chlorate Cl. O 3 -1 Chromate Cr. O 4 -2 Hydroxide OH -1 Nitrate Permanganate Phosphate -3 Sulfate NO 3 -1 Mn. O 4 -1 PO 4 SO 4 -2

Polyatomic ions act just like single-atom ions. They bond with ions of the opposite charge in the same way.

Binary Compound (made of 2 elements) Ca+2 Cl-1 with Ternary Compound (made of more than 2 elements -- includes a polyatomic ion) Ca+2 with NO 3 -1 Illustration: Cl-1 Ca+2 Cl-1 NO 3 -1 Ca+2 NO 3 -1 Formula: Ca Cl 2 Ca (NO 3)2

Instructions for constructing ionic compound activity. If needed, cut out ions. Match one type of cation (+ ion) with one type of anion (- ion) in ratios that result in a rectangle (zero overall charge).

Always list the positive ion first

Fill in the missing information Name Formula Charge Sulfate PO 4 Ammonium C 2 H 3 O 2 Mn. O 4 Nitrate CO 3 Hydroxide

Mini Quiz #4 Balance the following formulas K SO 4 Ba PO 4 NH 4 OH NH 4 C 2 H 3 O 2 Ba C 2 H 3 O 2 K Mn. O 4 NH 4 SO 4 NH 4 Cl Al NO 3 K OH Mg CO 3 K SO 4

Attachments Dogs Teaching Chemistry - Chemical Bonds. mp 4